Amistar for season long green growth in potatoes

Controlling soil pathogens at the time of potato planting can help encourage faster crop establishment and achieve quicker ground cover in the spring, according to Tom Whitworth of Syngenta. Trials results have shown that control of Rhizoctonia with Amistar application in the seedbed produced 60% greater ground cover two weeks post-emergence, he reports.

Furthermore, the beneficial effect on crop health and vigour helped maintain green leaf at the end of the season, when untreated crops had begun to die back. Twelve weeks after emergence of a crop of Markies, the Amistar treated crop still retained 82% ground cover, when untreated had dropped to just 70%.

"Rhizoctonia is believed to be having a far greater hidden effect on crop establishment and season-long vigour," warns Mr Whitworth. "Getting the crop growing faster is essential to optimise tuber set; the prolonged green leaf area at the end of the season can enhance tuber size and quality. In these JP Agronomy trials we saw significant yield increases of up to 20% from treatment with Amistar alone."

Furthermore, Mr Whitworth highlights that Rhizoctonia stem pruning – which could be the primary reason for the slower establishment – also causes late secondary tuber initiation. The result of which is inconsistent tuber size and variable dry matter at harvest, both of which can adversely affect processing and cooking quality of potatoes.

Amistar is the only approved treatment for soil-borne Rhizoctonia and Black Dot; trials and field experience have also shown a valuable reduction in Silver Scurf levels. In-furrow application at the time of planting creates an effective zone of protection around the mother tuber, whilst more growers are now using an overall pre-planting bed application and incorporation to treat 15-20cm of the soil profile and protect roots as they grow.

"Research has also identified that the interaction of free living nematode attacks and Rhizoctonia infection which can combine to seriously affect canopy development and final yield.

Using the combination of Amistar to control soil-borne pathogens and Nemathorin for free living nematodes and other soil pests can help ensure a clean seedbed for crops to get away," advises Mr Whitworth. "It’s now recognised that the benefit lasts all season and through to the final sale of higher quality tubers."

For further information visit www.syngenta-crop.co.uk